What is value stream mapping?

A Lean Tool for Understanding Flow

Value stream mapping (VSM) is a lean management method for analysing and designing the flow of materials and information required to bring a product or service to a customer. It was popularised by Mike Rother and John Shook in their 1999 book Learning to See.

Purpose

The primary purpose of a value stream map is to make the invisible visible. In most organisations, the flow of work is hidden — handoffs happen through emails, inventory sits in queues, and no one has a complete picture of end-to-end lead time. A value stream map puts all of this on one page.

Key concepts

• Value-added time — Time spent transforming the product or service in a way the customer would pay for.
• Non-value-added time — Waiting, transport, rework, and other activities that consume time but do not add value.
• Lead time — The total elapsed time from start to finish, including all waiting.
• Process efficiency — The ratio of value-added time to total lead time. Most processes are below 10% efficient.

When to use VSM

Value stream mapping is most useful when:

• You need to understand where time is being lost in a process.
• You are planning a lean transformation or continuous improvement initiative.
• You need to communicate process problems to stakeholders.
• You want to set measurable improvement targets.

The mapping process

1. Select the product or service family to map.
2. Create the current state map by walking the process.
3. Analyse the current state for waste and improvement opportunities.
4. Design the future state with improvements applied.
5. Implement changes and track progress.